Moisture determination



June 27, 1967 H. E. ALQUIST ETAL 3,327,735

MOISTURE DETERMINATION FIG. 4

PPM WATER 0) 20 4o IMIN. 20 40 2mm. 20 4o 3MIN.

TESTER FREEZING TIME r-* I 40 i 45 4 TTORNE rs United States Patent 3,327,735 MOISTURE DETERMINATION Henry E. Alquist and Dan. E. Smith, Bartiesville, Okla.,

assignors to Phillips Petroleum Company, a corporation of Delaware Original application Oct. 31, 1960, Ser. No. 66,104, now Patent No. 3,196,667, dated July 27, 1965. Divided and this application Sept. 18, 1964, Ser. No. 397,520

Claims. (Cl. 138-43) This application is a divisional of my copending application Ser. No. 66,104, filed Oct. 31, 1960, now Patent No. 3,196,667, granted July 27, 1965.

This invention relates to the determination of the mois ture content of fluids. In one aspect, this invention relates to an apparatus for determining the moisture content of a fluid, comprising snap acting means for changing from one to another of two flow restricters in a flow passage. In another aspect, this invention relates to a moisture tester comprising a flow passage and means to change from one flow restriction to another. In another aspect, this invention relates to a method for determining the moisture content of a fluid by flowing the fluid through a restriction to cool the testing zone and then flowing the fluid through a smaller opening and determining the time required for a shut-off due to freezing of the contained moisture.

Knowledge of the moisture content of various fluids often is an important consideration. For example, condensed moisture may interfere with the flow of gas in a pipe line and, under certain conditions of temperature and pressure, moisture may combine with a gaseous hydrocarbon to form gas hydrates. The solid product thus formed may collect in sufficient quantity to reduce the flow rate or even to plug completely the pipe line in which the flow is occurring. The specifications under which liquefied petroleum gases are sold often include the moisture content. Our invention is particularly suited for determining the moisture content of liquefied petroleum gas (LPG) hydrocarbons without restoring to laboratory analysis. The method and apparatus of our invention may be used by comparatively unskilled labor under conditions existing in commercial operations with accuracy suflicient to determine whether specific examples meet moisture specifications.

It is an object of this invention to provide a method and apparatus for determining the moisture content of fluids.

Another object of this invention is to provide a method j" and apparatus suitable for determining fluid moisture content under conditions of field operations. Another object of this invention is to provide a method and means for determining moisture content of fluids with which reproducible determinations can be made.

Other aspects, objects and the several advantages of this invention will be apparent from a study of this disclosure, the drawing and the appended claims.

The apparatus according to our invention comprises a body having a flow passage therethrough and means to provide a relatively mild restriction to flow and a relatively severe restriction to flow at will. The restrictions to flow may be provided by a flow restricting member, a portion of which is provided with two different flow restricting portions which may be inserted into the flow passage. Also, according to our invention, there is provided a flow restricting and positioning portion outside the flow passage, as well as the two portions which are inserted into the flow passage. Further, according to our invention, there are provided a moisture tester having a flow passage and a flow restricting member, the combination of which provides means for obtaining reproducible test results. Also, according to our invention, there is provided a method of determining the moisture content of a fluid by flowing the fluid through a testing zone having a restricted flow passage to cause expansion of the fluid and resulting cooling of the zone and further restricting the flow passage and determining the time required for the flow passage to plug due to freezing of contained moisture.

In the drawing, FIGURE 1 illustrates a combination of elements useful in determining the moisture content of a fluid. FIGURE 2 is a vertical cross section of a moisture tester, according to our invention. FIGURE 3 illustrates the flow control member of the moisture tester. FIGURE 4 is a graph showing the relationship between moisture content and tests made according to the present invention.

In FIGURE 1, a source of liquefied petroleum gas (LPG) is connected through a valve 11 and a pressure regulator 12 to moisture tester 20.

As shown in FIGURE 2, moisture tester 20. comprises a body 21, control housing 22, flow control member 23, spring 24, and cam lever 25. Body 21 is provided with inlet passage 26, outlet passage 27 and vertical flow passage 28. At the top of flow passage 28, there is provided a circular lip 29 having a substantially planar upper surface 30. Body 21 is also provided with threaded connections 31, 32 and 33 which connect with an inlet pipe, an outlet pipe and with control housing 22, respectively.

Control housing 22 connects with body 21 by threads 33, thereby providing a fluid tight seal therewith. There are also provided a cylinder 34 and a coaxial bore 35 through which flow control member 23 extends. As illustrated, spring 24 also extends upward within cylinder 34 and there are provided an O ring seal 36 and a sealing washer 37 in the upper portion of cylinder 34 to prevent leakage of fluid through bore 3-5.

Cam lever 25 comprises a handle portion 38, a recess 39 and cam surface 40. Lever 25 is attached to the upwardly extending stem 41 of control member 23 by a pin 41a.

Referring now to FIGURE 3, as well as to FIGURE 2, flow control member 23 comprises stem 41, seat 42, a first cylindrical portion 43, a second, smaller diameter, cylindrical portion 44 and a portion 45 having parallel planar sides 46 and 47 and arcuate sides 48 and 49. Seat 42 has a first substantially planar area 50, at right angles to the axis of the member 23, area 50 being provided with relieved portions 51 and 52. g a 1' With the various elements in the position illustrated in FIGURE 2, area 50 contacts a portion of the surface 30 of lip 29 to position flow control member 23 relative thereto. In this position, the portions 43, 44, and 45 are: all insideflow passage 28 and the restriction to flow of a fluid through this passage is the sum of the restriction provided by portions 43, 44 and 45, plus the restriction provided by the clearance between relieved areas 51 and 52 through which the fluid must flow to reach outlet passage 27. Member 23 is urged to this position and there maintained by spring 24 when lever 25 is placed in the position shown in FIGURE 2. When cam lever 25 is ro-' tated aboutpin 41a in the direction of the arrow, cam surface 40 engages the upper portion of control housing 22 and, as lever 25 is moved farther in the direction of the arrow, a force is exerted due to the cam action to raise member 23 a distance equal to the difference in the height of pin 41a from the upper surface of housing 22 and the distance from pin 41a to the cam surface 40 at right angles to a fiat portion of cam surprace 40 which is vertical in the position illustrated in FIGURE 2 but which is horizontal when lever 25 reaches the extreme of movement in the direction of the arrow, at which time this fiat surface cooperates with the upper surface of housing 22 to provide a stable position for lever 25 and, therefore,

for the entire movable assembly. This assembly obviously is stable in the position illustrated in FIGURE 2 as well.

3 With lever 25 rotated to the position in which flow control member 23 is lifted vertically in FIGURE 2, area 50 is of course, lifted from surface 30 and portion 43 is withdrawn from passage 28 while portion 45 remains therein,

member having a first cylindrical portion having a diameter slightly smaller than the diameter of said passage, a second cylindrical portion slightly smaller than said first cylindrical portion and adjacent thereto, a third portion the position preferably being one in which portion 44 is 5 adjacent said second portion having a pair of substantialpositioned opposite surface 30 of lip 29. ly parallel planar sides parallel with the axis of said cylin- In operation, when it is desired to determine the moisdrical portions and spaced apart a distance equal to the ture content of the fluid in source 10, lever 25 is rotated to diameter of said second cylindrical portion and a pair of raise member 23, as described above, and valve 11 is arcuate sides parallel with the axis of said cylindrical opened, allowing the fluid to flow through tester 20. Porportions and having a radius equal to the radius of said tion 45 of flow control member 23 provides a restriction first cylindrical portion, a seat adjacent said first portion in flow passage 28 which causes a pressure drop through having a first substantially planar area at right angles this area and, thus, an expansion of the fluid and conseto the axis of said passage, adapted to contact said surquent cooling of the body 21. When sufficient cooling has face, said area having relieved substantially planar areas been accomplished, the lever 25 is flipped into the posi- 15 adapted to be spaced a short distance from said surface tion illustrated in FIGURE 2, thus providing a much when said first area is in contact therewith, a stem atgreater restriction to flow through passage 28, an increased tached to said flow control member at one end and to a pressure drop and resulting increased expansion of the snap acting cam actuator at the other end, said actuator fluid and the resulting increased cooling efiect. This inbeing stable in two positions, in one of said positions said creased cooling efiect, in combination with the very small first cylindrical portion being Withdrawn from said pasavailable flow area in passage 28, results in plugging of sage and third portion being within said passage to prothis area with ice or hydrates. At the time lever is vide a limited restriction to flow through said passage, moved into the position shown in FIGURE 2, a stopwatch and, in another of said positions, said first cylindrical poris started and the time determined to the time of shut-ofi tion being within said passage and said area being in condue to plugging. This time is a function of the moisture 25 tact with said surface to allow very limited flow through content of the fluid flowing through the apparatus. said passage.

In one embodiment, flow passage 28 is finished to a 2. A moisture tester comprising a body having a fluid diameter of between .1285 and .1286 inch. The diameter passage therethrough, a flow control member, means to of portion 43 is between .1280 and .1281 inch and the retain said member in either of two stable positions and diameter of portion 44 is between .103 and .105 inch. The to move said member from either of said stable positions depth of the relief of portions 51 and 52 is between .005 to cause said member to be positioned unstable at any and .007 inch, portion 43 is from .085 to .087 inch long position between said two stable positions to the other, and portion 44 between .046 and .056 inch long and the said member in one of said stable positions cooperating total length of elements 43, 44 and 45 combined is bewith said body to provide a very small flow passage, and tween .194 and .196 inch. said member in the other of said stable positions cooperat- In a test using a moisture tester having the dimensions ing with said body to provide a still smaller flow passage. set out above, a series of six samples was obtained from 3. A moisture tester comprising a body having a fluid a stream from a propane dehydrator, the six samples corpassage therein, a substantially planar surface adjacent responding with six runs made to determine the freeze said passage, a flow control member comprising a seat time with the moisture tester described. The results of the having a substantially planar area parallel with said surtests are given in Table I and are plotted in the chart face and a relieved portion, a first flow restricting memof FIGURE 4. This chart is a plot of moisture tester her to cooperate with said passage to substantially restrict freezing time and the actual moisture content as deterthe flow therethrough, a second flow restricting member mined by laboratory tests of the samples taken. to cooperate with said passage to restrict the flow there- TABLE I Sample No. Date Time Moisture Line Freeze Time Water,

Tester Tempv p.p.rn

.m 2 60 3minutes 7 .m 2 1 60 15 seconds.-- 24 .m 1 60 30 seconds..- 14 2 65 27 seconds 20 2 65 seconds-.- 16 1 65 fiseeonds 75 1 Moisture tester 2 was on the dehydrator outlet. 2 Moisture tester 1 was on the dehydrator inlet.

Reasonable variation and modification are possible through, a smaller amount than said first flow restricting within the scope of the foregoing disclosure, the drawing member, a snap acting cam actuator operatively conand the appended claims to the in nti n t ss n of nected with said flow control member to retain said flow which is a moisture/tester comprising a W Passage f control member in either of two stable positions, to cause a flOW COH rOI member cooperating 'fi t0 Prowle said flow control member to be positioned unstable at more than one d g e of flow f ihTPugh the P any position between said two stable positions, and to Sage a methofi of detclimmmg the molsture f h move said member from either of said stable positions 0f 3 flmd y flowing the f through zoneaprovldnlllg to the other, in one of said stable positions, said planar f restpqnon to flow which p i m g area contacting said surface and said first and second 3. provldmgl a i 12 restnctm; 3 i g s flow restricting members being positioned in flow restrictfieezmg p uggmg F long an e g ing relation with said passage, and, in the other of said time required for such plugging. v

we c1 ai m stable positions, said planar area be ng removed from said L A moisture tester comprising a body having a m surface and said first flow restrict ng member being redrical passage and a circular lip surrounding one end of moyed f 110W tlngrelatlm with sa d passage the passage, said lip having a substantially planar surface whlle a second e restrwtms member remams 1n flow at right angles. to the axis of said passage, a flow control restriction relation with said passage.

4. A moisture tester, comprising: 5. A moisture tester comprising:

a first member having a cylindrical fluid passage therea first member having a fluid passage therethrough;

through; a flow control member; and

a flow control member comprising a stem having a means to move and retain said first member and said cylindrical portion having a diameter slightly smaller 5 flow control member into two stable relative posithan the diameter of said cylindrical passage, adapted tions, to cause said first member and said flow conto provide an annular passage of predetermined cleartrol member to be in unstable relative position at ance therebetween, when said cylindrical portion is extended into said cylindrical passage;

a spring to bias said flow control member toward and into a first position with respect to said first member wherein said moisture tester is open to flow only through said annular passage;

any relative position between said two stable positions and to change said stable relative positions one to the other, said first member and said flow member in one of said stable relative positions cooperating to provide a very small flow passage, and said first member and said flow control member in a snap acting cam actuator attached to said stem to move said flow control member against the force of 15 said spring into a second position with respect to said first member to open an additional passage through said moisture tester larger than said annular pasthe other of said stable relative positions cooperating to provide a still smaller flow passage.

References Cited UNITED STATES PATENTS sage; and 447,351 3/ 1891 Reynolds. means on said actuator to maintain said flow control 20 1,482,021 1/1924 Little 13843 member stable in said second position until released, 3,156,262 11/1964 Attebo 13843 said spring moving said flow control member into and retaining said flow control member in said first position upon release of said means.

LAVERNE D. GEIGER, Primary Examiner. T. L. MOORHEAD, Assistant Examiner. 

2. A MOISTURE TESTER COMPRISING A BODY HAVING A FLUID PASSAGE THERETHROUGH, A FLOW CONTROL MEMBER, MEANS TO RETAIN SAID MEMBER IN EITHER OF TWO STABLE POSITIONS AND TO MOVE SAID MEMBER FROM EITHER OF SAID STABLE POSITIONS TO CAUSE SAID MEMBER TO BE POSITIONED UNSTABLE AT ANY POSITION BETWEEN SAID TWO STABLE POSITIONS TO THE OTHER, SAID MEMBER IN ONE OF SAID STABLE POSITIONS COOPERATING 